An electrode wire is formed in a solar battery cell, or in an electronic component of a plasma display (PDP) or a liquid crystal display (LCD). Such an electrode wire is formed, using a conductive paste. Silver (Ag) or aluminum (Al) is used as metal particles for a conductive paste. An electrode wire is formed by firing a conductive paste in the atmosphere at a high temperature. Herein, in addition to metal particles, the conductive paste contains powder of a glass composition, and the glass composition becomes soft and flows when heated to a temperature higher than or equal to the softening point of the glass composition during firing of the conductive paste so that a silver electrode wire or an aluminum electrode wire becomes densified and firmly adhered to a substrate.
For this glass composition, used is a lead oxide (PbO) based glass composition that becomes soft and flows at a comparatively low temperature. However, as the lead oxide contained in the glass composition is a harmful material, in order to attain reduction in the environmental load, a lead free glass composition has come to be used for an electrode wire of a solar battery cell, an electronic component of a plasma display panel, or the like. For example, Patent Document 1 presents a lead free glass containing a bismuth oxide (Bi2O3) and a silicon oxide (SiO2) to be used for a silver (Ag) electrode wire or an aluminum (Al) electrode wire formed in a solar battery cell. Further, Patent Document 2 presents a lead free glass containing a bismuth oxide and a boron oxide (B2O3) to be used for an aluminum electrode wire formed in a solar battery cell.